1. Field of the Invention
Various embodiments of the present invention relate to a semiconductor device and a method of manufacturing the same, and more particularly, to a semiconductor device having a 3-dimensional cell string and a method of manufacturing the same.
2. Description of the Related Art
Generally, a cell string of a semiconductor device is formed in a 2-dimensional (2D) structure configured to form memory cells in a single-layer form on a substrate. A degree of integration of the 2D cell string may be enhanced by reducing the area of a plane occupied by the memory cells using a fine pattern forming method.
Since technologies that enhance the degree of integration for the above-described 2D cell string have reached a limit, a 3-dimensional (3D) cell string configured to stack memory cells in a multi-layer form on a substrate has been proposed. A degree of integration of this 3D cell string may be enhanced without reducing the area of a plane occupied by the memory cells.
The 3D cell string is formed along a channel structure passing through interlayer insulating layers and conductive patterns, which are alternately stacked on a substrate. The interlayer insulating layers and the conductive patterns may be penetrated by a slit and divided into a plurality of stack structures. The channel structure may be connected to conductive lines such as bit lines, source lines, etc. via a contact plug, which is connected over the channel structure.
Since a contact area between the contact plug and the channel structure is small, misalignment between the contact plug and the channel structure easily occurs during the fabrication processing. Hereinafter, causes of the misalignment between the contact plug and the channel structure are described in further detail.
After forming the slit, thermal stress may be applied to the substrate. Due to the thermal stress, the conductive patterns may be bent. When the number of the interlayer insulating layers and the conductive patterns that constitute the stack structure are increased to enhance a degree of integration of the 3D cell string, bending of the conductive patterns becomes more severe. When the conductive patterns are bent, the location of the channel structure passing through the conductive patterns may be changed. As a result, the misalignment between the contact plug and the channel structure may occur.